1. Field of Invention
The invention relates to the field of signal processing technology, and particularly to the processing of signals to reduce or prevent error propagation in communication and other systems.
2. Description of Related Art
In communication receiving stations, for example mobile cellular installations, systems equipped with multiple-antenna arrays offer improved receiver performance by sampling and processing the set of signals arriving on antenna channels, and weighting and combining them in efficient ways.
Antenna arrays, as discussed in U.S. Pat. No. 5,819,168 entitled "ADAPTIVE COMMUNICATION SYSTEM AND METHOD USING UNEQUAL WEIGHTING OF INTERFERENCE AND NOISE" filed May 1, 1997 and "TIME-SHIFTED WEIGHTING FOR SIGNAL PROCESSING" filed concurrently herewith and each assigned to the same assignees as this application and U.S. patent application Ser. No. 08/850,896 each incorporated here by reference, can reduce the effect of multipath fading and interference, by deriving weights for each channel that lead to improved receiver performance.
However, in known approaches for receiving the incoming signals to generate channel weights (using a data-derived reference signal), there is a danger that errors in weight generation and signal detection can propagate, causing catastrophic signal loss.
Because of the sequential nature of the processing of receiver signals, even a small error can result in a long error burst. In the weight generation technique reflected in the forementioned U.S. Patent Application "ADAPTIVE COMMUNICATION SYSTEM AND METHOD USING UNEQUAL WEIGHTING OF INTERFERENCE AND NOISE" for instance, the channel is characterized using a 14-symbol or other width sliding window, and deteriorating weight estimates render succeeding weight estimates worse, since the detected symbols used for weight generation are estimated less and less accurately. In the case of mobile wireless communication systems including industry standard IS-136, this can cause a user to lose their telephone or other connection completely. Techniques to avoid error propagation are therefore desirable.